Electric switch structure with improved printed circuit contact board assembly

ABSTRACT

A rotary switch having a rotor comprising at least one wiper assembly carried by a rotor spindle and having a stator comprising at least one printed contact board which has contacts thereon selectively engageable by said wiper assembly and through which the rotor spindle extends, said wiper assembly being slidably mounted on the rotor spindle which has a cross-sectional configuration for imparting rotary drive to said assembly and the rotor spindle being readily withdrawable from the printed contact board and its associated wiper assembly upon the release of axial restraining means normally acting on the spindle.

United States Patent I John Ashman [72] Inventor Ilford, England [21] Appl. No. 712,527 [22] Filed Mar. 12, 1968 [45] Patented Mar. 23, I971 [73] Assignee The Plessey Company Limited Ilford, England [32] Priority Mar. 15, 1967 [33] Great Britain [31] 12,054/67 [54] ELECTRIC SWITCH STRUCTURE WITH IMPROVED PRINTED CIRCUIT CONTACT BOARD ASSEMBLY 10 Claims, 4 Drawing Figs. [52] U.S.Cl 200/11, 200/14, 200/168 51 Int. Cl H01h; 19/58, I HOlh 19/64 [50] Field of Search 200/4, 11, 14, 168 (S) [56] ReferencesCited UNITED STATES PATENTS 2,576,836 11/1951 l-iilsinger 2,841,660 7/1958 Tabet 200/14 2,956,131 10/1960 Tabet 200/14 2,971,066 2/1961 Tabet ZOO/14X 2,988,607 6/1961 Tabet ZOO/14X 3,015,000 12/ 1 961 Tabet 200/14 3,242,270 3/1966 Van Volkenburg et al. 200/ 14X 3,242,271 3/1966 Stephan et al. 200/1 1 (D) 3,261,929 7/1966 Neff, Jr 200/11 (D) Pn'mary Examiner-Robert K. Schaefer Assistant Examiner-J. R. Scott Attorney-Scrivener, Parker, Scrivener and Clarke ABSTRACT: A rotary switch having a rotor comprising at 25 lllH 4l-- PATENTEU HAR23 I97! SHEET 1 [IF 2 PATENTED HAR23 I97:

SHEET 2 [IF 2 HUUUIF IIIIL ELECTRIC SWITCH STRUCTURE WITH TWROVED PRINTED CIRCUIT CONTACT BOARD ASSEMBLY This invention relates to electric switches and is more specifically concerned with electric switches of the rotary yp The present invention has specific application to rotary electric switches in which the switch rotor is constituted by a number of wiper assemblies carried by a rotor spindle and in which the stator of the switch consists of a number of printed contact boards having contacts printed thereon with which the wipers of the wiper assemblies selectively engage. By the term printed contact boards is meant boards having planar contacts which may or may not be provided by normal printing techniques.

An object of the present invention is to provide for the easy removal and insertion of printed contact boards in switches of the type set forth above.

According to the present invention there is provided a rotary switch having a rotor comprising at least one wiper assembly carried by a rotor spindle and having a stator comprising at least one printed contact board with contacts selectively engageable by said wiper assembly, said wiper assembly being slidably mounted on the rotor spindle which has a cross-sectional configuration effecting rotary drive to the wiper assembly and the rotor spindle being readily withdrawable from the printed contact board and the wiper assembly associated with it upon the release of axial restraining means normally acting on the spindle.

The switches to which, it is envisaged, the invention will especially be applied, will usually comprise a plurality of parallel printed contact boards and associated wiper assemblies, the boards being received by a slotted casing structure of the switch with edge connector means engaging printed contact terminals of the board. Thus, as the rotor spindle is withdrawn by sliding movement from the switch, the wiper assemblies and associated boards will be left in position thereby facilitating the withdrawal of one or more of such boards as for example for replacement of the boards by ones having different contact arrangements.

it may be arranged, for example, that the rotor spindle is withdrawn with the usual switch knob but it may also be arranged that the spindle is withdrawn through the knob after a spindle release operation has been carried out, or the spindle may be withdrawn after decoupling it from switch actuating means.

in carrying out the invention in one mode it is preferred to arrange that the rotor spindle is coupled to the output side of an indexing mechanism to the input side of which a rigid connection is made from the usual switch control knob or other actuating means.

By providing the rigid connection between the control knob and the indexing mechanism there will be a positive drive of the mechanism without any backlash by reason of the fact that the rotor spindle is coupled to the output of the mechanism and therefore manufacturing tolerances in the coupling (e.g. cooperating flats) between the rotor spindle and the indexing mechanism cannot produce backlash at the control knob.

The rigid connection referred to preferably comprises a hollow shaft through which the rotor spindle extends, conveniently beyond its coupling point to the indexing mechanism. The spindle may be retained axially by being clamped to the knob and hollow shaft assembly and thus may readily be withdrawn from the switch after the clamping force is removed.

in another mode of carrying out the present invention the rotor spindle is coupled to an indexing mechanism through a so-called Oldham coupling or the like which facilitates rotary drive of the spindle whilst permitting removal of the spindle from the coupling by the displacement of the switch assembly in a direction perpendicular to the spindle axis whereupon the rotor spindle can be withdrawn from the switch. The input side of the indexing mechanism may be directly coupled to a control knob through a short spindle while the output side of indexing mechanism is connected to the Oldham coupling. In this way backlash may be avoided in the manner aforesaid.

By the last-mentioned feature of the present invention rotary switches may be of modular form permitting the ready removal or replacement of the switch rotor/stator assembly from the switch drive control means (knob/indexing mechanism assembly) which may be left attached to a switch mounting panel.

By way of example two embodiments of the present invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic axial cross-sectional view of one rotary-type switch constructed in accordance with the invention;

FlG. 2 is a transverse sectional view of the switch of HO. 1 taken along the line A-A in P10. 1;

FIG. 3 is a diagrammatic side view of another rotary-type switch according to the present invention.

FIG. 4 is a partial perspective view of the switch of FIG. 1 illustrating the manner in which the printed boards are mounted in the switch casing.

Referring firstly to FIGS. 1 and 2 of the drawings the rotary switch illustrated comprises a rotor assembly including a rotor spindle l which, as can be seen in FIG. 2, has a part thereof of generally rectangular cross section. This spindle l carries for rotation therewith switch wiper assemblies each of which is of the form shown in FIG. 2. As can be seen these wiper assemblies comprise two double wiper contact members 3 and 4 secured to an insulating disc-shaped support 5. Each wiper assembly is adapted for wiping over printed contacts located on one side of a double-sided printed board such as the boards 7 and 8 which are slidingly received by grooves extending down inner sidewalls of a switch casing and provided by members 40 secured to those walls. End walls of the switch casing are shown at 9 and 10. The disc supports 5 of pairs of wiper assemblies are locked together in the manner shown in FIG. 1 by means of interengaging studs and holes indicated at ll and 12, respectively, so that the central cylindrical part 13 of the interlocked disc supports extends through holes 14 in the printed boards 7 and 8. It will be appreciated therefore that two wiper assemblies are attached to each of the printed boards 7 and 8 but that these pairs of assemblies are each rotatable relative to the printed board to which they are attached so that the wipers 4 selectively engage printed contacts such as contacts 41 on the printed boards.

It will be appreciated that the interlocking of the wiper assemblies enables the rotor spindle l to be withdrawn endwise from the switch without disturbing the wiper assemblies which remain attached to the printed boards.

The rotor spindle l is conveniently rotatably supported at its lefthand end by means of a gearing surface l5. The spindle 1 passes through an indexing mechanism l6 which may be of the conventional spring ball type and is rotatably coupled to the output thereof at B7 through flats 18 on the spindle. The spindle i also extends through a short hollow shaft or spindle 19 which extends from the indexing mechanism 16. This hollow spindle 19 has a control knob 20 secured to it by means of a grub screw 21 so that there is a direct positive backlash-free connection between the control knob 20 and the input of the indexing mechanism 16 through the spindle 19. The spindle 19 is arranged for rotation through a sealing gland 22 formed integrally with end wall 10 and which also serves for securing the switch casing to a mounting or control panel 23. The knob 20 has a threaded bore 23 into which threads a plug 25 which bears against the flanged spindle end 26 so as the spindle ll axially and to compress a sealing ring 27 between the plug 25 and the end of the shaft 29 thereby to effect sealing between the spindle l and the shaft 19 at the knob end of the assembly.

The end of the spindle 19 has a threaded hole 28 formed therein to facilitate the attachment of a tool for the withdrawal of the spindle 1 from the assembly without disturbing the knob 29 or the indexing mechanism lie.

From the foregoing it will be appreciated that the knob 20 is rigidly coupled to the indexing mechanism 16 and that any free play in the coupling between the rotor spindle l and the output side of the mechanism 16 due to manufacturing tolerances in the interengaging flats is not transferred back to the control knob.

Turning now to the other embodiment depicted in FIG. 3 of the drawings, this shows in outline a rotary switch assembly module 29 which is of similar construction to the switch of H68. l and 2 having a rotor spindle which can be withdrawn from printed boards and associated wiper assemblies. The rotor spindle of the assembly is indicated at 30 and is of generally rectangular cross section at the end thereof shown where it forms part of a so-called Oldham coupling indicated generally at Kill for rotation of the spindle 30. The Oldham coupling may be provided on the output side of indexing mechanism 32 which is clamped to a control panel 33 by means of a nut 34 threaded on to a threaded spigot 35 passing through a hole in the panel. Through the spigot 35 extends a spindle as to which a knob (not shown) may be secured and which may be coupled to the input side of the indexing mechanism 32 or the spindle 36 may be directly secured to the Oldham coupling 31 with the spindle 36 simply actuating the indexing mechanism through cooperating flats on the spindle and mechanism. The Oldham coupling enables the rotor spindle 3t) and thus the switch module as a whole to be displaced away from the indexing mechanism/control knob assembly in a direction perpendicular to the axis of the spindle by prviding cooperating guide members or surfaces 37 and 38. Thus the entire module can readily be removed from or replaced on to the panel asmmbly. The spindle 34 can then be withdrawn from the switch module by axial movement of the spindle.

In both of the switch constructions described and illustrated with respect to FIGS. l and 2 electrical connections to the printed boards constituting the switch stators may be made through edge connectors such as that shown at 39 in FIGS. 1 and 3.

lelaim:

l. A rotary switch having a rotor comprising at least one wiper assembly carried by a straight rotor spindle and having a stator comprising at least one printed circuit contact board which has contacts thereon selectively engageable by said wiper assembly and through which the rotor spindle extends, said printed circuit contact board being slidably mounted for movement into and out of a switch casing and said wiper assembly being slidably mounted on the rotor spindle which has a cross-sectional configuration for imparting rotary drive to said assembly and the rotor spindle being readily withdrawable in the axial direction of the rotor spindle from the printed contact board and its associated wiper assembly upon the release of axial restraining means normally acting on the spindle at the drive end of the spindle which is the end from which the spindle is withdrawn.

2. A rotary switch as claimed in claim 1, comprising a plurality of parallel printed contact boards printed on both sides and having associated wiper assemblies.

3. A rotary switch as claimed in claim 2, in which the boards are received in slots of a slotted switch casing and board terminal contacts are engaged by edge connector means.

4. A rotary switch as claimed in claim 1, in which the rotor spindle is arranged to be withdrawn through the knob after a spindle release operation is carried out.

5. A rotary switch as claimed in claim I. in which the rotor spindle is arranged to be withdrawn from the switch after sliding disconnection of the spindle from a slotted coupling which normally couples the switch to switch-actuating means.

6. A rotary switch as claimed in claim 5, in which the rotor spindle is coupled to an indexing mechanism through an Oldham coupling or the like which facilitates rotary drive of the spindle while permitting removal of the spindle from the coupling by the displacement of the switch assembly in a direction perpendicular to the spindle axis whereupon the spindle can be withdrawn from the switch. I

7. A rotary switch as claimed in claim 6, m WhICl'l the input side of the indexing mechanism may be directly coupled to a control knob through a short spindle while the output side of indexing mechanism is connected to the Oldham coupling.

8. A rotary switch as claimed in claim 1, in which the rotor spindle is coupled to the output side of an indexing mechanism to the input side of which a rigid connection is made from the usual switch control knob or other switch actuating means.

9. A rotary switch as claimed in claim 8, in which the rigid connection comprises a hollow shaft through which the rotor spindle extends beyond its coupling point to the indexing mechanism.

10. A rotary switch as claimed in claim 9, in which the rotor spindle is normally restrained axially by being clamped to the switch knob which is fixedly secured to the hollow shaft and into which the rotor spindle projects. 

1. A rotary switch having a rotor comprising at least one wiper assembly carried by a straight rotor spindle and having a stator comprising at least one printed circuit contact board which has contacts thereon selectively engageable by said wiper assembly and through which the rotor spindle extends, said printed circuit contact board being slidably mounted for moVement into and out of a switch casing and said wiper assembly being slidably mounted on the rotor spindle which has a cross-sectional configuration for imparting rotary drive to said assembly and the rotor spindle being readily withdrawable in the axial direction of the rotor spindle from the printed contact board and its associated wiper assembly upon the release of axial restraining means normally acting on the spindle at the drive end of the spindle which is the end from which the spindle is withdrawn.
 2. A rotary switch as claimed in claim 1, comprising a plurality of parallel printed contact boards printed on both sides and having associated wiper assemblies.
 3. A rotary switch as claimed in claim 2, in which the boards are received in slots of a slotted switch casing and board terminal contacts are engaged by edge connector means.
 4. A rotary switch as claimed in claim 1, in which the rotor spindle is arranged to be withdrawn through the knob after a spindle release operation is carried out.
 5. A rotary switch as claimed in claim 1, in which the rotor spindle is arranged to be withdrawn from the switch after sliding disconnection of the spindle from a slotted coupling which normally couples the switch to switch-actuating means.
 6. A rotary switch as claimed in claim 5, in which the rotor spindle is coupled to an indexing mechanism through an Oldham coupling or the like which facilitates rotary drive of the spindle while permitting removal of the spindle from the coupling by the displacement of the switch assembly in a direction perpendicular to the spindle axis whereupon the spindle can be withdrawn from the switch.
 7. A rotary switch as claimed in claim 6, in which the input side of the indexing mechanism may be directly coupled to a control knob through a short spindle while the output side of indexing mechanism is connected to the Oldham coupling.
 8. A rotary switch as claimed in claim 1, in which the rotor spindle is coupled to the output side of an indexing mechanism to the input side of which a rigid connection is made from the usual switch control knob or other switch actuating means.
 9. A rotary switch as claimed in claim 8, in which the rigid connection comprises a hollow shaft through which the rotor spindle extends beyond its coupling point to the indexing mechanism.
 10. A rotary switch as claimed in claim 9, in which the rotor spindle is normally restrained axially by being clamped to the switch knob which is fixedly secured to the hollow shaft and into which the rotor spindle projects. 